Start by installing powerline using these docs:
http://powerline.readthedocs.org/en/master/installation.html
Install powerline-gitstatus (do not use the provided config files):
https://github.com/jaspernbrouwer/powerline-gitstatus#installation
A .config directory for powerline should have been created, if it wasn't for some reason create the powerline directory inside your .config directory.
Once you've created the powerline directory copy the contents from my repo in the powerline directory to your powerline directory:
https://github.com/gravyboat/powerline-config/powerline
The key file that no one seems to mention is the config.json. This will force the actual changes to take effect, and without this file you'll still be using the default configuration. While that may work I prefer everything aligned on the left side of the screen.
Once this is complete check to make sure the linting is fine with powerline-lint and if everything looks fine restart the daemon with powerline-daemon --replace. You should now see the status of the git repo on the powerline prompt when you're in a repo directory.